76 2.0l FI stock engine bucks under 2000 rpm and load Options

[jdlmodelt]

Hi guys,
My 76 2.0l stock Fuel Injected engine is bucking when I press on the throttle to accelerate when the engine is under 2000RPM. Above that the engine is smooth and strong but below that point when I step on the throttle going down the hiway, it either bucks, stutters and doesn't accerate or doesn't buck but doesn't accellerate either. It is backfiring a little more than ussual as well. It let out a couple of big bangs at the tail pipe yesterday when I was down shifting to a stop light at lower speeds. So, running super rich at lower RPM? I changed the timing last week to smooth out the low idle. I'm guessing that may be some of it?

BUT, I was wondering if the throttle possition sensor needs to be adjusted along with the timing? It seems like there is some kind of relationship in the lower RPMS amongst the ignition timing, the injector timing, the throttle position sensor and the anti-backfiring valve?
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